Because the performance of joints is not evaluated as a part of the
general ASTM E 119 or UL 263 fire test, Section 715 addresses
the situations where breeches occur “in or between” assemblies,
providing the details and test standards to be used for determining
compliance. Joint firestop systems that are in compliance with
Section 715 will: a. Accommodate cyclical movement of the adjacent
assemblies; b. Prevent the passage of flames and hot gases sufficient
to ignite cotton waste to the unexposed side of the assembly; and
c. For joints that are part of a wall assembly, remain in place when
subjected to the hose stream test. The hose stream test simulates
pressures and impacts such as building components falling and
shocking the joint firestop. As the saying goes, a chain is only as
strong as its weakest link. By extension, if a fire-resistance-rated
assembly does not have its breeches adequately protected with
fire-resistant joint systems, then the effectiveness of the assembly
is compromised.
JOINT SYSTEMS IN SMOKE BARRIERS
The last provision in Section 715 addresses situations where a joint
occurs within a smoke barrier and mandates that the joint should
have an L rating (a leakage rating) that does not exceed 5 cubic
feet per minute (cfm) of air leakage per linear foot of joint length at
0.30 inch of water for both the ambient temperature and elevated
temperature tests. This air leakage rate must be determined using
the UL 2079 test standard since the ASTM E 1966 standard does
not include this rating and as such is not referenced under the fire
test criteria of Section 715.6. The provisions of Section 715.6 are
applicable to both horizontal assemblies serving as smoke barriers
as well as walls constructed in accordance with Section 709. As
per IBC, smoke barriers may be required or installed at a number of
locations including:
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